Cue the standard reactions you would expect from the major players. Donald Trump took to the stage at his next campaign rally and solemnly (well, with what passes for solemnity when delivered by Trump) told his supporters that there had been a critically important development in the campaign, relaying the news of the FBI’s reopened investigation to tumultuous cheers from the crowd. He went on to claim that the developing story was “bigger than Watergate“.

Meanwhile, the cable news channels, grateful for anything which disrupts the rather predictable “Clinton romping to near-certain victory” narrative which is so bad for ratings, eagerly talked up the “bombshell” development.

I think Comey has to have found something significant to have done this. Re-injecting himself into the presidential campaign eleven days before the election is not something he would do lightly or happily. But I have no idea what that something might be.

I agree. James Comey has a reputation to protect, one which will not be enhanced by making himself the sudden focus of the presidential election campaign this close to polling day if it turns out that there is nothing to the newly discovered email stash. Serious conversations would have gone on before Comey made the final decision to write that letter to congressional committee chairmen informing them of his decision to reopen the investigation, and that alone counts for something.

Goldberg continues:

I’m more confident, however, that if the Clinton campaign was holding back any opposition research in reserve, it is now very likely to get dropped like the payloads from a squadron of B-52 bombers. So far the Clinton camp has been very, very skillful in deploying its oppo. It doesn’t rush things and has been comfortable letting story lines develop. (Yes the Trump team is right that many of these sexual abuse stories are “orchestrated.” But “orchestrated” isn’t a synonym for “untrue”).

What would that oppo look like? I don’t know. But, unless there’s something much worse than the “groping” storyline we already know, the sexual-abuse charges are now baked in with most of the public (and among Republican apologists). Until today, that was probably fine with the Clinton camp because she’s been on course for a big win. If you’re in the clear lead, the incentive to drop more oppo is not there because there’s always the risk of blowback.

But the polls have tightened a little. More troubling for her is the fact that between the Doug Band story and now this, Clinton is likely to be in the spotlight for the next few days or longer. (By the way, how happy is Doug Band to be wiped out of the news cycle?) And the dilemma for Clinton is that whichever candidate is in the spotlight tends to suffer in the polls because the American people don’t like either of them.

And that’s why I think we can expect the Clintonites to do what they do best: change the subject from their wrongdoing to someone else’s, presumably Donald Trump’s. Maybe it won’t happen, but I wouldn’t be surprised if by the time the Sunday shows are on, or by Monday morning at the latest, we’ll have at least two “bombshells” to discuss.

Most people I have spoken to seem agreed that Hillary Clinton is holding something back in reserve – an additional Trump scandal (either real or confected) different in tone and nature to the others, which could be deployed as a kind of political doomsday device if Clinton found herself behind in the polls or facing serious political difficulties going into the home stretch. Anyone who knows how the Clintons operate would probably concur that this would be absolutely in character.

The only question, to my mind, is whether Hillary Clinton panics and deploys her doomsday device now, in an attempt to change the narrative and avoid losing a whole weekend’s worth of news cycles, or if she holds her nerve and waits to see any potential wobble in the tracking polls before deciding whether or not to take action.

As Jonah Goldberg rightly points out, there are disadvantages to unleashing an opposition research-generated political doomsday device this close to the end of the election. If the scandal is “good” enough, it could succeed in driving more moderate Trump supporters away or depressing his overall voter turnout. But if it is perceived as being little different to a restatement of Donald Trump’s personal flaws which have already been “priced in” by his supporters then it will make little positive difference, while potentially tarring Clinton with having used underhanded tactics in the home stretch.

There is no margin for error in this decision, so if we do see a big revelation from Hillary Clinton it will be a good sign that her campaign is seriously worried – and perhaps that they do not have full confidence in the many polls which have shown her maintaining a consistent lead over Donald Trump.

So while on face value this has been a rare good news day for the Trump campaign – probably the best since Hillary Clinton’s “medical episode” in New York on 9/11 – rather than rejoicing and taking a premature victory lap, now might actually be the time for the Donald Trump campaign and his supporters to hunker down and prepare for the worst.

Sticking their heads above the parapet to enjoy the spectacle of Hillary Clinton flailing in response to new questions about her improper use of email may be tempting and even cathartic, but it also increases the risk of being taken by surprise in the event of the deployment of Hillary’s Revenge.

If Hillary Clinton has something, anything else on Donald Trump, the temptation now comes hardest upon her to use it. This election campaign has either been blown wide open in Donald Trump’s favour, or is about to be slammed shut in his face.